Aspect Ratio Calculator

Resize images and videos without the weird stretching. Enter your original dimensions and one new value, and the other one fills in automatically.

Original Size

New Size

Type in one field and the other updates on the fly.

Aspect Ratio

? : ?

Quick Ratios

Common Resolutions

How the math works

Pretty straightforward. If you know the original dimensions and one new dimension, the formula is:

new_height = (orig_h / orig_w) * new_width
or
new_width = (orig_w / orig_h) * new_height

About this tool

If you've ever resized an image and ended up with something that looks squished or stretched, you probably weren't keeping the aspect ratio. This calculator takes the guesswork out of it. Punch in the original width and height, then start typing a new width or height and it'll fill in the other value as you go. Handy for responsive design, video editing, thumbnail generation, or really any time you need to scale something without distorting it.

Auto-calculates as you type, no extra clicks needed
Shows simplified aspect ratio (e.g. 16:9)
Quick presets for common ratios and resolutions
Visual preview of the proportions
Swap width and height with one click
Runs entirely in your browser, nothing gets sent anywhere